Automated external defibrillator systems with operation adjustment features according to temperature and methods of use

ABSTRACT

The disclosure describes various aspects of an automated external defibrillator (AED) system, including shock generating electronics, a battery configured for providing power to the shock generating electronics, power management circuitry configured for managing the shock generating electronics and the battery, at least one environmental sensor configured for monitoring environmental conditions in which the AED system is placed, and a controller configured for controlling the power management circuitry and the at least one environmental sensor. The at least one environmental sensor includes a temperature sensor configured for providing a temperature measurement, and the controller is further configured for adjusting operations of the power management circuitry in accordance with the temperature measurement provided by the temperature sensor. The disclosure further describes associated methods of using the AED system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/501,616 filed Oct. 14, 2021, now U.S. Pat. No. 11,413,467, whichclaims the benefit of U.S. Provisional Patent Application Ser. No.63/091,681 filed Oct. 14, 2020, both entitled “Automated ExternalDefibrillator Systems With Operation Adjustment Features According ToTemperature And Methods Of Use”, the disclosures of which are hereinincorporated by reference in their entirety.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to automated externaldefibrillators (AEDs) and, more particularly, to compact AED systems.

BACKGROUND OF THE DISCLOSURE

86 million Americans have risk factors for sudden cardiac arrest (SCA),while 12 million are at high risk. Cardiac events represent more deathsin America than breast, lung, colon and prostate cancer combined. Morethan 360,000 sudden cardiac arrest (SCA) occur outside of the hospitaleach year. According to the American Heart Association, nearly 70percent of these SCAs occur at home, out of reach of the lifesavingshock of an AED

As each minute passes following a sudden cardiac arrest, the chances ofsurvival decrease significantly. If an AED is not applied within 10minutes of a SCA event, chances of survival decrease to less than 1%.

One approach to increasing the chance of survival for SCA sufferers isto make AEDs more readily available and accessible for more people.However, the AEDs currently available on the market tend to be heavy,not portable, expensive, and intimidating to use for people withoutmedical training. For example, U.S. Pat. Pub. No. U.S. 2018/0169426,entitled “Automatic External Defibrillator Device and Methods of Use,”which disclosure is incorporated herein in its entirety by reference,provides a possible solution to overcome the availability andaccessibility problem by providing a compact AED device suitable forportability.

Aspects of the present disclosure provide techniques and structures thatimprove the performance of AEDs suitable for high portabilityapplications.

SUMMARY OF THE DISCLOSURE

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its purpose is to presentsome concepts of one or more aspects in a simplified form as a preludeto the more detailed description that is presented later.

In an aspect, an automated external defibrillator (AED) system isdescribed, in accordance with an embodiment. The AED system includesshock generating electronics, a battery configured for providing powerto the shock generating electronics, power management circuitryconfigured for managing the shock generating electronics and thebattery, at least one environmental sensor configured for monitoringenvironmental conditions in which the AED system is placed, and acontroller configured for controlling the power management circuitry andthe at least one environmental sensor. The at least one environmentalsensor includes a temperature sensor configured for providing atemperature measurement, and the controller is further configured foradjusting operations of the power management circuitry in accordancewith the temperature measurement provided by the temperature sensor.

In another aspect, a method for using an external defibrillator (AED)system is described, in accordance with an embodiment. The AED systemincludes shock generating electronics, a battery configured forproviding power to the shock generating electronics, power managementcircuitry configured for managing the shock generating electronics andthe battery, at least one environmental sensor for monitoringenvironmental conditions in which the AED system is placed, and acontroller configured for controlling the power management circuitry andthe at least one environmental sensor. The method includes measuring atemperature of the AED system, and adjusting operations of the powermanagement circuitry in accordance with the temperature so measured.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings illustrate only some implementations and aretherefore not to be considered limiting of scope.

FIG. 1 illustrates a block diagram of an exemplary AED, including an AEDoperations block and a communications block, in accordance with anembodiment.

FIG. 2 illustrates a flow diagram of a process for adjusting theoperation of an AED taking into consideration a measured batterytemperature, in accordance with an embodiment.

FIG. 3 illustrates a flow diagram of a process for adjusting theoperation of an AED taking into consideration a measured padstemperature, in accordance with an embodiment.

DETAILED DESCRIPTION

The present invention is described more fully hereinafter with referenceto the accompanying drawings, in which embodiments of the invention areshown. This invention may, however, be embodied in many different formsand should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. In the drawings, the size andrelative sizes of layers and regions may be exaggerated for clarity.Like numbers refer to like elements throughout.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present invention

Spatially relative terms, such as “beneath,” “below,” “lower,” “under,”“above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. It will beunderstood that the spatially relative terms are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. For example, if the device inthe figures is turned over, elements described as “below” or “beneath”or “under” other elements or features would then be oriented “above” theother elements or features. Thus, the exemplary terms “below” and“under” can encompass both an orientation of above and below. The devicemay be otherwise oriented (rotated 90 degrees or at other orientations)and the spatially relative descriptors used herein interpretedaccordingly. In addition, it will also be understood that when a layeris referred to as being “between” two layers, it can be the only layerbetween the two layers, or one or more intervening layers may also bepresent.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items, and may be abbreviated as “/”

It will be understood that when an element or layer is referred to asbeing “on,” “connected to,” “coupled to,” or “adjacent to” anotherelement or layer, it can be directly on, connected, coupled, or adjacentto the other element or layer, or intervening elements or layers may bepresent. In contrast, when an element is referred to as being “directlyon,” “directly connected to,” “directly coupled to,” or “immediatelyadjacent to” another element or layer, there are no intervening elementsor layers present. Likewise, when light is received or provided “from”one element, it can be received or provided directly from that elementor from an intervening element. On the other hand, when light isreceived or provided “directly from” one element, there are nointervening elements present.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present specification and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

If more AEDs can be made available to more people, with improvedportability, lower cost, and enhanced ease of use, then more lives canbe saved in the event of an SCA occurring outside of a hospital setting.That is, like an EpiPen® injector is prescribed for and carried by thosediagnosed with potentially life-threatening allergies, a portable AEDcan be a necessary and routine item prescribed to those diagnosed asbeing at risk for SCA. A portable, affordable, and user-friendly AEDwith safe and simple application protocol is desired for suchwide-spread proliferation of AEDs in the consumer market. Additionally,secure and streamlined connections to emergency personnel, external datasources, and peripheral devices would also be desirable.

One challenge to having a portable AED is the necessity to ruggedize theAED such that the system can be stored and is operable in a variety ofenvironmental conditions, such as at low and high altitudes, low andhigh humidity, and low and high temperatures (e.g., minus 20° C. to +50°C.). As the various components within the AED can function differentlyin different environmental conditions, and even the physical conditionsof the patient (e.g., skin temperature) can impact the operation of theAED, it would be desirable for the portable AED to be able to adjust tovarying environmental conditions during storage and in operation,preferably in real time.

Referring now to FIG. 1 , an exemplary AED including an AED operationsblock and a communication block, in accordance with an embodiment, isillustrated AED 100 includes features that allow AED 100 to be connectedwith the outside world so as to provide additional functionality andallow use scenarios that have been heretofore impossible. An AED 100includes an AED operations block 102, which includes various componentsthat enable AED 100 to generate and deliver, within regulatoryguidelines, an electric shock to a person in Sudden Cardiac Arrest. Asshown in the embodiment illustrated in FIG. 1 , AED operations block 102includes a controller 110, which regulates a variety of componentsincluding an electrocardiogram (ECG) monitoring circuitry 120, which isin turn connected with pads 122. Pads 122 are configured for attachmentto specific locations on the SCA patient for both obtaining ECG signalsand administering the electric shock generated by shock generatingelectronics 124, which is also controlled by controller 110. Controller110 also monitors the condition of the pads, for example by measuring aface-to-face pads impedance. Increased pads impedance may indicate thatthe adhesives for attaching the pads to the SCA patient may be overlydry, thus requiring replacement to maintain effective operation of theAED system.

Additionally, AED operations block 102 includes a power management block130, which is also controlled by controller 110 in an embodiment. Powermanagement block 130 is configured for managing the power consumption byvarious components within AED operations block 102. For instance, powermanagement block 130 monitors a charge status of a battery 132, whichprovides power to shock generating electronics 124. As such, controller110 can alert the AED user if a low battery level is detected by powermanagement block 130. Similarly, controller 110 can also regulate powermanagement block 130 to control the on/off status of other componentswithin AED 100 so as to minimize the power consumption by these othercomponents while the AED is not being used. In an embodiment, forexample, power management block 130 is configured to completely powerdown ECG monitoring circuitry 120 and shock generating electronics 124when the AED is not being used. Controller 110 may include, for example,non-transitory memory for storing software instructions. Thenon-transitory memory may be communicatively coupled with a processor(e.g., microprocessor) for executing software instructions stored on thenon-transitory memory. Software instructions may include, for instance,workflow information for operating the AED, as described herein.

Continuing to refer to FIG. 1 , controller 110 is also connected with amemory 140, which stores information regarding AED 100, such as usehistory, battery status, shock administration and cardiopulmonaryresuscitation (CPR) protocols, and other information (e.g., stored inlook-up tables) used in the operation of AED 100.

Controller 110 further controls a user-interface (UI) block 150. UIblock 150 includes, for example, voice and/or visual prompts forinstructing the AED user on the use of AED 100 as delivered by a userinterface, such as a haptic display such as a touch screen, lightemitting diode (LED) indicators, liquid crystal display, speakers,switches, buttons, and other ways to display information to the userand/or for a user to control the AED In an embodiment, UI block 150 canoptionally include a microphone to receive voice inputs from the AEDuser. In an alternative embodiment, UI block 150 can optionally includean interface with an external application, such as a native or web appon a mobile device configured for communicating with AED 100.

AED Operations Block 102 as shown in FIG. 1 further includes optionalfeatures such as wireless charging circuitry 160 and accelerometer 162.For example, if a portion of battery 132 includes a rechargeable batteryconfigured for wireless charging, then wireless charging circuitry 160is used to charge the rechargeable battery. Optionally, power managementblock 130 can be used to control wireless charging circuitry 160 totrigger the battery charging process when the charge level of therechargeable battery within battery 132 is detected to have fallen belowa preset threshold. Alternatively, power management block 130 maytrigger the battery charging process using a wired connection with anexternal power source (e.g., an electrical wall socket, car charger, ora power generator—not shown), when the charge level has fallen below apreset threshold. The optional accelerometer 162 may be used todetermine whether the AED has been moved. If readings from theaccelerometer indicate that the AED has been moved, an AED locationcheck may be performed to determine new GPS coordinates and/or atemperature check may be performed using AED temperature sensors todetermine environmental conditions at the new AED location.

Additionally, an environmental sensor block 164 can be used to monitorthe environmental conditions in which AED 100 is placed. For instance,environmental sensor block 164 can include one or more of a temperaturesensor, a hygrometer, an altimeter, and other sensors for monitoring theenvironments around AED 100 and/or one or more components within orcoupled to the AED 100. As an example, environmental sensor block 164monitors the temperature of battery 132 and/or pads 122, and/or therelative humidity of the environment in which the AED is placed.

Still referring to FIG. 1 , AED 100 includes a communications block 170,also controlled by controller 110. Communications block 170 providesconnections to external systems and entities outside of the AED, such asemergency medical services, hospital emergency rooms, physicians,electronic health record systems, as well as other medical equipment,such as ventilators and an external ECG. In an embodiment,communications block 170 optionally includes a cellular modem 172 and aBluetooth® modem 174. Optionally, communications block 170 alsoincludes, for example, a Wi-Fi modem 176 for providing wirelessconnection to and from an external device, one or more wired connections178 for providing direct wired connection to AED 100 such as via a localarea network (LAN), cable, phone line, or optical fiber. Communicationsblock 170 can also optionally include a satellite modem 180 forproviding remote communications via satellite. The various communicationmodes within communications block 170 are configured to comply withregulatory guidance related to wireless technology, such as coexistence,security, and electromagnetic compatibility. By having a singlecontroller (e.g., a microprocessor) control the various blocks withinAED 100, the circuit design and firmware configuration of AED 100 isgreatly consolidated over other AEDs with multiple processors, whileenabling a reduction in power consumption of the device.

Environmental conditions, such as temperature and humidity, affect boththe performance of the AED in use and degradation rate of AED componentsduring storage and transport. For example, it has been long recognizedthat the adhesives on the pads degrade more quickly at highertemperature such that others have suggested adjusting the regularreplacement schedule of the pads according to the temperature conditionsof the location at which the AED is stored and used, even without theAED and the pads having been deployed prior to replacement. Also, thebatteries that power the AED operation have degradation rates that varywith temperature. For example, U.S. Pat. No. 6,980,859 to Powers, etal., mentions that the degradation rate of disposable batteries issimilar to the degradation rate of the pads with respect to temperature.

Further, it is recognized herein that the particular temperature of thebattery and pads can have implications on the safe operation of the AED,both during transport/storage and during shock delivery. By taking intoaccount the ambient temperature and/or temperature at specificcomponents within the AED, adjustments can be made by the powermanagement module and/or by the controller within the AED operationsblock to enable safer and more reliable operation of the AED

I. Accounting for Temperature in Battery Charge Level Assessment

The ambient or battery temperature can be taken into account inunderstanding the charge status of the battery. This temperatureinformation can then be used to adjust the rate at which the shockgenerating electronics in the AED are charged. For example, the chargerate of the shock generating electronics may be reduced when the batteryis at a cold temperature or at a low battery level in order to avoid abrownout situation where the controller and other circuits are not beable to function due to low power supply voltage from the battery.

An example of a process for using temperature data to adjust operationsof the AED is shown in FIG. 2 . A process 200 of FIG. 2 begins with astart step 202, followed by a step 210 to measure the temperature of thebattery within the AED, such as battery 132 of AED 100. For example,environmental sensor block 164 may include a thermometer, athermocouple, or thermistor device (e.g., a resistance temperaturedetector) for measuring the temperature of battery 132 and/or theexternal environment in which AED 100 is used. Optionally, the ambienttemperature of the AED or another component within the AED may be usedas a proxy for the battery temperature.

Process 200 proceeds to a step 212 to measure the voltage level(“batt_level”) of the battery, thus providing an indication of how muchcharge can be provided by the battery at the time of interest (e.g., atthe time the measurement is taken). For example, measurement of thevoltage level of battery 132 can be performed by power management block130.

TABLE 1 Battery Level Thresholds (V) Low Critical Battery 25° C. 10.59.2 Temperature  0° C. 8.6 8.0 (° C.) −20° C.  7.6 6.8

In an example, a look-up table (e.g., TABLE 1 shown herein) can be usedto determine specific battery level thresholds below which the batteryvoltage would be considered low or critically low. For example, if thebattery voltage is determined to be low, then the AED controller maysend a notification to a user. Due to the dependence of the measuredbattery voltage on battery temperature, it is recognized herein that thelow and critically low battery level thresholds should be adjustedaccording to the battery temperature. Table 1 reflects an example set ofthreshold values considered suitable for effective operation of anexemplary AED It should be noted that, while TABLE 1 shows thetemperature values as measured at the battery, another temperaturereading at a different portion of the AED, such as ambient temperatureor the internal temperature of the AED case, may be used as proxy to thebattery temperature. Threshold temperature levels may be adjusteddepending on the location at which the temperature measurement is taken.

While the threshold values shown in TABLE 1 are for specific batterytemperatures, a linear or nonlinear interpolation approach may be usedto extend the data in TABLE 1 to temperatures below, above, and betweenthe listed values. For example, a nonlinear regression (e.g., nonlinearleast squares fittings) can be used to find a suitable function thatbest fits a given set of data points. An example approach can be foundat http://www.xuru.org/rt/NLR.asp.

Returning to FIG. 2 , a decision 220 is made to determine whether themeasured battery temperature is greater than a high temperaturethreshold (e.g., 25° C.). If the answer to decision 220 is YES, then thevalue of variable batt_temp to be used in the threshold interpolation isset to the high temperature threshold value (e.g., 25° C.) in a step222. If the answer to decision 220 is NO, process 200 proceeds to adecision 224, in which a determination is made whether the measuredbattery temperature is less than the low temperature threshold (e.g.,−20° C.). If the answer to decision 224 is YES, then batt_temp is set tothe low temperature threshold value (e.g., −20° C.). in a step 226. Ifthe answer to decision 224 is NO, then batt_temp is set to the measuredbattery temperature value in a step 228.

From steps 222, 226, and 228, process 200 proceeds to a step 230, inwhich the voltage threshold value low_level (i.e., the voltage valuebelow which the battery charge level would be considered to be too lowfor safe operation of the AED) is calculated for the given value ofvariable batt_temp. The equation used to calculate low_level takes intoaccount the variable batt_temp as set in step 222, 226, or 228. Asdescribed above, this equation can be obtained by calculating anequation that fits the data given in TABLE 1. Similarly, in a step 232,the voltage threshold value crit_level (i.e., the voltage value belowwhich the battery charge level would be considered to be critically lowfor safe operation of the AED) is calculated for the value of givenvariable batt_temp. Then a determination is made in a decision 240whether the value of batt_level measured in step 212 is below thecalculated voltage threshold value crit_level from step 232. If theanswer to decision 240 is YES, then an indication is noted at the AEDcontroller that the battery charge level is critically low in a step242. If the answer to decision 240 is NO, then a determination is madein a decision 244 whether the value of batt_level is below thecalculated voltage threshold value low_level from step 230. If theanswer to decision 244 is YES, then an indication is noted at the AEDcontroller that the battery charge level, while not critically low, isstill considered low in a step 246. If the answer to decision 244 is NO,then an indication is noted at the AED controller that the batterycharge level is normal at step 248. Following step 242, 246, or 248, theoperation of the AED is adjusted according to whether the battery levelis critically low, low, or normal in a step 250.

For instance, if the AED is actively in use to prepare to shock apatient, and the battery voltage level is determined to be low orcritically low using process 200, then the power management block mayslow the charge rate of the shock generating electronics to avoidquickly draining the battery. In another example, process 200 may takeplace during a self-test routine of the AED In such a case, if thebattery voltage level is low or critically low, then an alert may besent to a registered user of the AED to recommend charging the AEDbattery as soon as possible. Alternatively, the power management blockmay automatically enable wired or wireless charging of the battery.Finally, process 200 is terminated in an end step 260.

While process 200 is shown with separate determinations for low andcritically low battery levels, either one of these determinations may beeliminated for simplicity of calculation while staying within the scopeof the present disclosure. Also, the specific values shown in TABLE 1and used in the calculations in process 200 are exemplary only, and arenot intended to be limiting. Process 200 may take place, for example, atcontroller 110 or power management block 130 of AED 100 in FIG. 1 .

II. Estimate Pads Impedance Based on Temperature

Another way to take temperature into account during AED operation is indetermining the status of the pads. As discussed earlier, the pads usedin transmitting electric shock to a SCA patient degrade over time, andthe pad degradation accelerates when stored at higher temperatures. Oneway to quantify pads degradation is by taking a face-to-face impedancemeasurement between the pair of pads. The face-to-face measurementprocess may include allowing electrical communication between faces ofthe two pads (e.g., by direct contact between portions of each face ofthe pads or by electrical coupling of a conductive wire between thefaces of the two pads) and sending an electrical signal through the padsto determine an impedance thereof. Whereas temperature dependence of thepads impedance can be taken into account during AED use (i.e., when thepads are applied to a SCA patient) without explicit measurement andadjustment specifically for temperature because the voltage/currentdetection during the first fraction of a second of the shock deliveryprotocol takes any pads impedance variations into account, alternativecurrent (AC) face-to-face measurements of the pads impedance, adjustedfor temperature, can be used to check for pads degradation.

TABLE 2 Pads Impedance (ohms) Pad Set #1 Pad Set #2 Pad Set #3 Pad Set#4 Pad Set #5 Pads 50° C. 1.1 Ω 2.1 Ω  1.9 Ω 0.9 Ω 1.9 Ω Temperature 20°C. 8.8 Ω 8.9 Ω 10.8 Ω 9.1 Ω 9.0 Ω (° C.) −20° C.  166.2 Ω  152.0 Ω 160.2 Ω  162.4 Ω  151.0 Ω 

TABLE 2 shows the experimentally measured face-to-face impedance betweenexemplary pairs of pads at different temperatures. The face-to-faceimpedance of pads stored at a given temperature over one year increasedonly slightly after three years of storage at the same temperature.While elevated impedance measurement is an indication that the pads maybe degraded, it is also recognized from the values in TABLE 2 that padsimpedance measurements also increase at lower temperatures.

TABLE 3 Pads Impedance Threshold (ohms) Pads Temperature  25° C.  40 Ω(° C.) −20° C. 240 Ω

Similar to the battery voltage level threshold determination, the padsimpedance threshold values may be experimentally derived for specificuse temperatures, then extrapolated using linear interpolation. TABLE 3shows example values of empirically determined pads impedance thresholdvalues at different temperatures. Then a linear interpolation may beused to adjust the pads impedance threshold value at temperaturesbetween a low temperature threshold and a high temperature threshold(e.g., −20° C. and 25° C., respectively).

An example of a process for adjusting the AED operation according to thedetermined condition of the pads is shown in FIG. 3 . A process 300 ofFIG. 3 begins with a start step 302, followed by a step 310 to measurethe temperature of the pads stored with or within the AED As describedabove with respect to the temperature measurement at the battery, thepads temperature measurement may be taken by environmental sensor block164 of AED 100 shown in FIG. 1 , and the ambient temperature or thetemperature of another component within the AED may be used as a proxyfor the pads temperature. Process 300 then proceeds to measure the padsimpedance (i.e., face-to-face impedance measurement) of the pads in astep 312. The pads impedance measurement may be performed, for example,by controller 110 of FIG. 1 .

Continuing to refer to FIG. 3 , a decision 320 is made to determinewhether the measured pads temperature is greater than the hightemperature threshold (e.g., 25° C.). If the answer to decision 320 isYES, then the value of variable pads_temp to be used in the thresholdinterpolation is set to the high temperature threshold value (e.g., 25°C.) in a step 322. If the answer to decision 320 is NO, then process 300proceeds to a decision 324, in which a determination is made whether themeasured pads temperature is less than the low temperature threshold(e.g., −20° C.). If the answer to decision 324 is YES, then pads_temp isset to the low temperature threshold value (e.g., −20° C.) in a step326. If the answer to decision 324 is NO, then pads_temp is set to themeasured pads temperature value, or a proxy thereof, in a step 328.

From steps 322, 326, and 328, process 300 proceeds to a step 330, inwhich the impedance threshold value high_level (i.e., the value abovewhich the pads impedance would be considered to be too high for safeusage of the pads) is calculated for the given temperature value ofvariable pads_temp. The equation used to calculate high_level takes intoaccount the variable pads_temp as set in step 322, 326, or 328.

Still referring to FIG. 3 , a determination is made in a decision 340whether the value of pads impedance measured is above the calculatedthreshold value high_level from step 330. If the answer to decision 340is YES, then at step 342, an indication is noted at the AED controllerthat the pads may be degraded such that they are unsafe for further use.If the answer to decision 340 is NO, then an indication is noted at theAED controller that the pads condition is normal in a step 348.Following step 342 or 348, the operation of AED is adjusted in a step350 according to whether the pads condition is determined to be degradedor normal. For example, if the condition of the pads are determined tobe normal, then an indication may be displayed on the AED or sent to aregistered user that a self-test of the pads indicates that the padscondition is normal and that they are ready for use. If the self-testindicates that the pads may be degraded, then an alert may be sent tothe registered user to urge replacing the pads as soon as possible or,if the AED is in use for providing an electric shock to a SCA patient,an alert may be displayed in a user interface to warn the user that thepads may be degraded and the AED performance may be compromised. Process300 is terminated in an end step 360. Process 300 may take place, forexample, at controller 110 of AED 100 of FIG. 1 .

Additional operations of the AED may be modified based on thetemperature measurements and pad impedance measurements described above.For example, thresholds for CPR feedback such as a compression ratethreshold and/or a compression depth threshold may be modified. CPRimpedance thresholds may also be adjusted based on the temperatureand/or pad impedance measurements.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. For instance, AED 100 may further includea global positioning system (GPS) transceiver as part of satellite modem180. Then, AED 100 may use GPS signals to determine, for instance, thegeographical location and altitude, which information may be used inconsidering the environmental conditions in which the AED is placed,such as described above. Alternatively, GPS data may be obtained usinganother component in communications block 170, such as cellular modem172, Bluetooth modem 174, Wi-Fi modem 176, and/or wired connection 178.

Features described above as well as those claimed below may be combinedin various ways without departing from the scope hereof. The followingexamples illustrate some possible, non-limiting combinations:

(A1) An automated external defibrillator (AED) system includes shockgenerating electronics, a battery configured for providing power to theshock generating electronics, power management circuitry configured formanaging the shock generating electronics and the battery, at least oneenvironmental sensor configured for monitoring environmental conditionsin which the AED system is placed, and a controller configured forcontrolling the power management circuitry and the at least oneenvironmental sensor. The at least one environmental sensor includes atemperature sensor configured for providing a temperature measurement,and the controller is further configured for adjusting operations of thepower management circuitry in accordance with the temperaturemeasurement provided by the temperature sensor.

(A2) For the AED system denoted as (A1), the power management circuitrymay be further configured for measuring a voltage level of the battery,and the controller may be further configured for comparing the voltagelevel of the battery so measured with at least one voltage thresholdlevel. The voltage threshold level may be selected based on thetemperature measurement provided by the temperature sensor.

(A3) For the AED system denoted as (A1) or (A2), a user interface may beconfigured for displaying information to a user of the AED system. Thecontroller may be further configured for providing an indication at theuser interface, in accordance with the voltage level of the battery someasured in comparison with the at least one voltage threshold level.

(A4) For the AED system denoted as any of (A1) through (A3), inaccordance with the voltage level of the battery so measured incomparison with the at least one voltage threshold level, the controllermay be further configured for instructing the power management circuitryto set a charge rate of the shock generating circuitry.

(A5) For the AED system denoted as any of (A1) through (A4), thecontroller may be configured for instructing the power managementcircuitry to reduce the charge rate of the shock generating circuitrywhen the voltage level of the battery is less than the at least onevoltage threshold level.

(A6) For the AED system denoted as any of (A1) through (A5), a wirelesscharging mechanism may be configured for wirelessly charging thebattery. In accordance with the voltage level of the battery so measuredin comparison with the at least one threshold level, the powermanagement circuitry may be further configured for initiating a processto charge the battery.

(A7) For the AED system denoted as any of (A1) through (A6), a pair ofpads may be provided for transmitting an electric shock from the shockgenerating electronics to a patient. The controller may be furtherconfigured for measuring a face-to-face impedance value between the pairof pads, and the controller may be further configured for comparing theface-to-face impedance value between the pair of pads so measured withat least one impedance threshold level. The impedance threshold levelmay be selected based on the temperature measurement provided by thetemperature sensor.

(A8) For the AED system denoted as any of (A1) through (A7), a userinterface may be configured for displaying information to a user of theAED system. The controller may be further configured for providing anindication to the user interface, in accordance with the face-to-faceimpedance value between the pair of pads so measured in comparison withthe at least one impedance threshold level.

(A9) For the AED system denoted as any of (A1) through (A8), thecontroller may be configured for providing an indication to the userinterface when the face-to-face impedance value is greater than the atleast one impedance threshold level.

(B1) A method for using an automated external defibrillator (AED) systemincludes the AED system including shock generating electronics, abattery configured for providing power to the shock generatingelectronics, power management circuitry configured for managing theshock generating electronics and the battery, at least one environmentalsensor for monitoring environmental conditions in which the AED systemis placed, and a controller configured for controlling the powermanagement circuitry and the at least one environmental sensor. Themethod includes measuring a temperature of the AED system, and adjustingoperations of the power management circuitry in accordance with thetemperature so measured.

(B2) For the method denoted as (B1), the method may include measuring avoltage level of the battery, and comparing the voltage level of thebattery so measured.

(B3) For the method denoted as (B1) or (B2), the AED system may furtherinclude a user interface, and the method may further include providingan indication at the user interface, in accordance with the voltagelevel of the battery so compared.

(B4) For the method denoted as any of (B1) through (B3), in accordancewith the voltage level of the battery so measured in comparison with theat least one threshold level, the method may include modifying a chargerate of the shock generating circuitry.

(B5) For the method denoted as any of (B1) through (B4), the method mayinclude measuring the temperature of the AED system including oneselected from a group consisting of measuring a temperature of thebattery, measuring an internal temperature of an AED case, and measuringan environment temperature.

Accordingly, many different embodiments stem from the above descriptionand the drawings. It will be understood that it would be undulyrepetitious and obfuscating to literally describe and illustrate everycombination and subcombination of these embodiments. As such, thepresent specification, including the drawings, shall be construed toconstitute a complete written description of all combinations andsubcombinations of the embodiments described herein, and of the mannerand process of making and using them, and shall support claims to anysuch combination or subcombination.

What is claimed is:
 1. A method for using an automated externaldefibrillator (AED) system, the AED system including shock generatingelectronics, a battery configured for providing power to the shockgenerating electronics, power management circuitry configured formanaging the shock generating electronics and the battery, a temperaturesensor configured for providing a temperature measurement, and acontroller configured for controlling the power management circuitry andthe temperature sensor, the method comprising: measuring a temperatureof the AED system via the temperature sensor, measuring a voltage levelof the battery via the power management circuitry, comparing via thecontroller the voltage level of the battery so measured with at leastone voltage threshold level, wherein the voltage threshold level isselected based on the temperature measurement provided by thetemperature sensor, in accordance with the voltage level of the batteryso measured in comparison with the at least one voltage threshold level,instructing the power management circuitry via the controller to set acharge rate of the shock generating circuitry, measuring a face-to-faceimpedance value between a pair of pads, the pair of pads beingconfigured for transmitting an electric shock from the shock generatingelectronics to a patient, comparing the face-to-face impedance valuebetween the pair of pads so measured with at least one impedancethreshold level, wherein the impedance threshold level is selected basedon the temperature measurement provided by the temperature sensor, andproviding an indication via a user interface when the face-to-faceimpedance value is greater than the impedance threshold level.
 2. Themethod of claim 1, further comprising: providing an indication of thecharge rate via a user interface.
 3. The method of claim 1, furthercomprising: instructing the power management circuitry to reduce thecharge rate of the shock generating circuitry when the voltage level ofthe battery is less than the at least one voltage threshold level. 4.The method of claim 1, further comprising: charging the battery via thepower management circuitry, wherein the AED system comprises a wirelesscharging mechanism configured for wirelessly charging the battery.